The Puffer Forum

If I had BW running, both my GH and KH would be higher than the mix provides, as I used OE-RFUG with aragonite in BW to boost both. I have a suspicion that the GH/KH is more important to the long-term health of our BW puffers than the salt or specific gravity, but I have no data to back it up. I would not sweat the elevated readings myself, but cheer them - JMHO, YMMV -

But why would it only take a few tablespoons to achieve the same SG it takes me cups?

For that answer you would have to play with the brands cited - milling and compounding themselves have a huge role in the density of the resulting mix, even without considering the hydroscopic nature of the components of the mix. The finer the milling, the less volume the mix occupies, but the caking problems from moisture increase with the fineness equally or more.

That's an interesting point about the fineness - the "New Improved" Instant Ocean I have claims disolvability is improved and the stuff is nearly as fine as powdered sugar (well, maybe not that fine, but it's close).

Eric

Two beta cups ~4/5 full of Instant Ocean mixed in a 5 gallon bucket not quite full of water usually yields about 1.017 for me, give or take a .001 or two. Then there's the occassional "oops" where these oh-so-scientific measuring techniques yield results that are much higher or much lower, so I always verify readings with my refractometer.

What do the instructions say on the box of salt?

The instructions suggest 1/2 cup per gallon for SW at 1.020 to 1.023 (I'm partially infering this - they actually say to make small batches of SW use 1/2 cup per gallon and earlier they mention SW should be in the SG range I listed).

Lets see...1/4 cup would get 1.010 to 1.012, so 1/8 cup would get 1.005 to 1.006 (I'm rounding on the high range to a digit my hydrometer would read). 1/8 cup = 2 tablespoons

So, according to the box 1 tablespoon per gallon should get to a SG about 1.0025 to 1.003. I confessed earlier that my bucket was 4, not 5 gallons and not full, so using 4 slightly rounded tablespoons in 3.5 gallons (which I thought before was 4 tablespoons in a not full 5 gallon bucket - hence 1 tablespoon per gallon) means I'm likely using 4.5 to 5 real tablespoons which is 1.28 to 1.43 tablespoons per gallon.

I'm not a math guy, but it seems highly feasible the SG I'm achieving could be 1.005 plus or minus .001 which is the range of both my hydrometers.

OK, I'm really tired now (cyphering is hard on my head)...night everyone.

Eric

I could never get sensible GH readings on BW or SW tanks. And, in fact, every test kit I have explicitly states that the GH test is "freshwater only".

And, in a related story, last week, my LFS ran out of buckets of Instant Ocean (reliable supply is always a problem in China). Unfortunately, the bags seem to take the "long route" upon importation, and the salt inside is usually "cloddy"/partially congealed. What took me just under 3 beakers of salt to get 1.026 before, required nearly five beakers.

I aged the mix for a few days and tested alkalinity.... 5dKH... tested calcium... 200ppm. I lost all faith in the mix (who knows what chemical changes would have taken place?) and threw the rest of the bag in the bin, and have switched to a "dry" bag of Reef Crystals instead.

Although I've never tested GH in my tanks (that I can recall), I do know that it only takes 1/2 cup (level) of Instant Ocean for every 5 gallons of water to get an SG of 1.006. I use a heaping 1/2 cup full when the bag of Instant Ocean is a few weeks old and caked up a bit to get the same SG.

Since my swing arm hydrometer (Instant Ocean brand) is actually reading spot-on compared to the refractometer at my LFS, and I know PP needs much more marine mix to achieve the same SG, I've also been wondering why and how PP needs more mix per gallon of tap water than I for the same SG.

Jayhawk, that whole breakdown is what I figured as well... but when I used a 1/4 cup in 2 gallons of water I only got 1.002. But when I added the second 1/4 cup, it jumped to 1.009. Pretty touchy...

Myaj - I'm beginning to think the entire process of measuring SG is closely tied into the practice of alchemy.

Eric

Only when volume measures are used, or rather relied on to mean something...

Call me old fashioned, but I shall always consider someone offering to buy me a pint a meaningful volume measure.

Also bear in mind that "specific gravity" is not an absolute measure anyway. The "buoyancy" of watr is dependent on a whole host of things in addition to the salt content -- temperature, air pressure (?).

So even that nice scale with "salinity" on one side and "specific gravity" on the other is somewhat fudged.

Salinity, on the other hand, should be a more constant parameter (but almost impossible to directly measure AFAIK)